21 resultados para Debt to growth relationship

em Helda - Digital Repository of University of Helsinki


Relevância:

100.00% 100.00%

Publicador:

Resumo:

In this paper both documentary and natural proxy data have been used to improve the accuracy of palaeoclimatic knowledge in Finland since the 18th century. Early meteorological observations from Turku (1748-1800) were analyzed first as a potential source of climate variability. The reliability of the calculated mean temperatures was evaluated by comparing them with those of contemporary temperature records from Stockholm, St. Petersburg and Uppsala. The resulting monthly, seasonal and yearly mean temperatures from 1748 to 1800 were compared with the present day mean values (1961-1990): the comparison suggests that the winters of the period 1749-1800 were 0.8 ºC colder than today, while the summers were 0.4 ºC warmer. Over the same period, springs were 0.9 ºC and autumns 0.1 ºC colder than today. Despite their uncertainties when compared with modern meteorological data, early temperature measurements offer direct and daily information about the weather for all months of the year, in contrast with other proxies. Secondly, early meteorological observations from Tornio (1737-1749) and Ylitornio (1792-1838) were used to study the temporal behaviour of the climate-tree growth relationship during the past three centuries in northern Finland. Analyses showed that the correlations between ring widths and mid-summer (July) temperatures did not vary significantly as a function of time. Early (June) and late summer (August) mean temperatures were secondary to mid-summer temperatures in controlling the radial growth. According the dataset used, there was no clear signature of temporally reduced sensitivity of Scots pine ring widths to mid-summer temperatures over the periods of early and modern meteorological observations. Thirdly, plant phenological data with tree-rings from south-west Finland since 1750 were examined as a palaeoclimate indicator. The information from the fragmentary, partly overlapping, partly nonsystematically biased plant phenological records of 14 different phenomena were combined into one continuous time series of phenological indices. The indices were found to be reliable indicators of the February to June temperature variations. In contrast, there was no correlation between the phenological indices and the precipitation data. Moreover, the correlations between the studied tree-rings and spring temperatures varied as a function of time and hence, their use in palaeoclimate reconstruction is questionable. The use of present tree-ring datasets for palaeoclimate purposes may become possible after the application of more sophisticated calibration methods. Climate variability since the 18th century is perhaps best seen in the fourth paper study of the multiproxy spring temperature reconstruction of south-west Finland. With the help of transfer functions, an attempt has been made to utilize both documentary and natural proxies. The reconstruction was verified with statistics showing a high degree of validity between the reconstructed and observed temperatures. According to the proxies and modern meteorological observations from Turku, springs have become warmer and have featured a warming trend since around the 1850s. Over the period of 1750 to around 1850, springs featured larger multidecadal low-frequency variability, as well as a smaller range of annual temperature variations. The coldest springtimes occurred around the 1840s and 1850s and the first decade of the 19th century. Particularly warm periods occurred in the 1760s, 1790s, 1820s, 1930s, 1970s and from 1987 onwards, although in this period cold springs occurred, such as the springs of 1994 and 1996. On the basis of the available material, long-term temperature changes have been related to changes in the atmospheric circulation, such as the North Atlantic Oscillation (February-June).

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Defence against pathogens is a vital need of all living organisms that has led to the evolution of complex immune mechanisms. However, although immunocompetence the ability to resist pathogens and control infection has in recent decades become a focus for research in evolutionary ecology, the variation in immune function observed in natural populations is relatively little understood. This thesis examines sources of this variation (environmental, genetic and maternal effects) during the nestling stage and its fitness consequences in wild populations of passerines: the blue tit (Cyanistes caeruleus) and the collared flycatcher (Ficedula albicollis). A developing organism may face a dilemma as to whether to allocate limited resources to growth or to immune defences. The optimal level of investment in immunity is shaped inherently by specific requirements of the environment. If the probability of contracting infection is low, maintaining high growth rates even at the expense of immune function may be advantageous for nestlings, as body mass is usually a good predictor of post-fledging survival. In experiments with blue tits and haematophagous hen fleas (Ceratophyllus gallinae) using two methods, methionine supplementation (to manipulate nestlings resource allocation to cellular immune function) and food supplementation (to increase resource availability), I confirmed that there is a trade-off between growth and immunity and that the abundance of ectoparasites is an environmental factor affecting allocation of resources to immune function. A cross-fostering experiment also revealed that environmental heterogeneity in terms of abundance of ectoparasites may contribute to maintaining additive genetic variation in immunity and other traits. Animal model analysis of extensive data collected from the population of collared flycatchers on Gotland (Sweden) allowed examination of the narrow-sense heritability of PHA-response the most commonly used index of cellular immunocompetence in avian studies. PHA-response is not heritable in this population, but is subject to a non-heritable origin (presumably maternal) effect. However, experimental manipulation of yolk androgen levels indicates that the mechanism of the maternal effect in PHA-response is not in ovo deposition of androgens. The relationship between PHA-response and recruitment was studied for over 1300 collared flycatcher nestlings. Multivariate selection analysis shows that it is body mass, not PHA-response, that is under direct selection. PHA-response appears to be related to recruitment because of its positive relationship with body mass. These results imply that either PHA-response fails to capture the immune mechanisms that are relevant for defence against pathogens encountered by fledglings or that the selection pressure from parasites is not as strong as commonly assumed.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Atmospheric aerosol particles have a significant impact on air quality, human health and global climate. The climatic effects of secondary aerosol are currently among the largest uncertainties limiting the scientific understanding of future and past climate changes. To better estimate the climatic importance of secondary aerosol particles, detailed information on atmospheric particle formation mechanisms and the vapours forming the aerosol is required. In this thesis we studied these issues by applying novel instrumentation in a boreal forest to obtain direct information on the very first steps of atmospheric nucleation and particle growth. Additionally, we used detailed laboratory experiments and process modelling to determine condensational growth properties, such as saturation vapour pressures, of dicarboxylic acids, which are organic acids often found in atmospheric samples. Based on our studies, we came to four main conclusions: 1) In the boreal forest region, both sulphurous compounds and organics are needed for secondary particle formation, the previous contributing mainly to particle formation and latter to growth; 2) A persistent pool of molecular clusters, both neutral and charged, is present and participates in atmospheric nucleation processes in boreal forests; 3) Neutral particle formation seems to dominate over ion-mediated mechanisms, at least in the boreal forest boundary layer; 4) The subcooled liquid phase saturation vapour pressures of C3-C9 dicarboxylic acids are of the order of 1e-5 1e-3 Pa at atmospheric temperatures, indicating that a mixed pre-existing particulate phase is required for their condensation in atmospheric conditions. The work presented in this thesis gives tools to better quantify the aerosol source provided by secondary aerosol formation. The results are particularly useful when estimating, for instance, anthropogenic versus biogenic influences and the fractions of secondary aerosol formation explained by neutral or ion-mediated nucleation mechanisms, at least in environments where the average particle formation rates are of the order of some tens of particles per cubic centimeter or lower. However, as the factors driving secondary particle formation are likely to vary depending on the environment, measurements on atmospheric nucleation and particle growth are needed from around the world to be able to better describe the secondary particle formation, and assess its climatic effects on a global scale.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Poetics of Awakenings. Genres and Intertexts in Arvid Järnefelt s Novels Isänmaa, Maaemon lapsia and Veneh ojalaiset This doctoral dissertation focuses on Arvid Järnefelt s (1961 1932) novels Isänmaa (1893), Maaemon lapsia (1905) and Veneh ojalaiset (1909). The study applies the genre theory and concepts Alastair Fowler has introduced in his Kinds of Literature (1982). Fowler s theory of the novel is developed further and applied to Finnish realist novels. The generic analysis is supplemented by intertextual analysis, which is mainly based on the idea of specific intertextual relations as presented by Kiril Taranovsky. Generic and intertextual analyses form the basis for hermeneutic interpretation, in which attention is paid to the fact that the novels are written by the designated writer in specific historical and cultural circumstances. Instead of the author s intention , the study focuses on the realised intention , in other words the novels as they are published. Järnefelt s first novel Isänmaa is understood to be a classical Bidungsroman that depicts the socialisation of a young male protagonist. From an intertextual point of view, the novel appears to be a novel of conversion, too, due to the biblical allusions concealed in the depiction of the events. Furthermore, Isänmaa is seen to stand in an intertextual relation to Hegel s, Snellman s and Topelius s writings. Maaemon lapsia is argued to be a thesis novel, which persuades the reader to adopt a certain ideological and political stance, namely Henry George s view on the private ownership of land. The novel is modulated by the generic repertoires of fairy tale and tragedy. The mythical frame of the novel supports the thesis novel, as it gives universal validity to the particular events depicted in the novel. Maaemon lapsia also comments on the contemporary political debate on the relations between Finland and Russia by presenting the relationship as analogous to the relationship between tenant farmer and landowner. Veneh ojalaiset exhibits a wide range of genres. Comic, tragic and mythical mode is combined with, for example, family novel, romance, conversion novel and revolutionary novel. From a rhetorical viewpoint, the novel is an apology, which accuses society of generating criminality by means of unjust laws and procedures. The novel discusses the question of resistance to evil by using the themes of Faust and Job, as well as by confronting the philosophies of Epictetus and Nietzsche. The novel is a thesis novel, which disputes the possibility of violent revolution as a way to a better society and recommends passive resistance for an individual living in an unjust society. The poetics of Järnefelt s novels is regarded as the poetics of conversion, as all the novels in focus depict the protagonist s awakening to see the society in a new light, be it a patriotic vision of the reality or a conception of the unfairness of society.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The study is a philosophical analysis of Israel Scheffler’s philosophy of education, focusing on three crucial conceptions in his philosophy: the conception of rationality, the conception of human nature, and the conception of reality. The interrelations of these three concepts as well as their relations to educational theorizing are analysed and elaborated. A conceptual problem concerning Scheffler’s ideal of rationality derives from Scheffler’s supposition of the strong analogy between science education and moral education in terms of the ideal of rationality. This analogy is argued to be conceptually problematic, since the interconnections of rationality, objectivity, and truth, appear to differ from each other in the realms of ethics and science, given the presuppositions of ontological realism and ethical naturalism, to which Scheffler explicitly subscribes. This study considers two philosophical alternatives for solving this problem. The first alternative relates the analogy to the normative concept of personhood deriving from the teleological understanding of human nature. Nevertheless, this position turns out to be problematic for Scheffler, since he rejects all teleological thinking in his philosophy. The problem can be solved, as it is argued, by limiting Scheffler’s rejection of teleology – in light of his philosophical outlook on the whole – in a manner that allows a modest version of a teleological conception of human nature. The second alternative, based especially on Scheffler’s later contributions, is to suggest that reality is actually more complex and manifold than it appears to be in light of a contemporary naturalist worldview. This idea of plurealism – Scheffler’s synthesis of pluralism and realism – is represented especially in Scheffler’s contributions related to his debate with Nelson Goodman dealing with both constructivism and realism. The idea of plurealism is not only related to the ethics-science-distinction, but is more widely related to the relationship between ontological realism and the incommensurable systems of description in diverse realms of human understanding. The Scheffler-Goodman debate is also analysed in relation to the contemporary constructivism-realism debate in educational philosophy. In terms of educational questions, Scheffler’s plurealism is argued as offering a fruitful perspective. Scheffler’s philosophy of education can be interpreted as searching for solutions to the problems deriving from the tension between the tradition of analytical philosophy and the complexity and multiplicity of educational reality. The complexity of reality combined with the supposition of the limitedness of human knowledge does not lead Scheffler to relativism or particularism, but, in contrast, Schefflerian formulations of rationality and objectivity preserve the possibility for critical inquiry in all realms of educational reality. In light of this study, Scheffler’s philosophy of education provides an exceptional example of combining ontological realism, epistemological fallibilism, and the defence of the ideal of rationality, combined with a wide-ranging understanding of educational reality.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Premature birth and associated small body size are known to affect health over the life course. Moreover, compelling evidence suggests that birth size throughout its whole range of variation is inversely associated with risk for cardiovascular disease and type 2 diabetes in subsequent life. To explain these findings, the Developmental Origins of Health and Disease (DOHaD) model has been introduced. Within this framework, restricted physical growth is, to a large extent, considered either a product of harmful environmental influences, such as suboptimal nutrition and alterations in the foetal hormonal milieu, or an adaptive reaction to the environment. Whether inverse associations exist between body size at birth and psychological vulnerability factors for mental disorders is poorly known. Thus, the aim of this thesis was to study in three large prospective cohorts whether prenatal and postnatal physical growth, across the whole range of variation, is associated with subsequent temperament/personality traits and psychological symptoms that are considered vulnerability factors for mental disorders. Weight and length at birth in full term infants showed quadratic associations with the temperamental trait of harm avoidance (Study I). The highest scores were characteristic of the smallest individuals, followed by the heaviest/longest. Linear associations between birth size and psychological outcomes were found such that lower weight and thinness at birth predicted more pronounced trait anxiety in late adulthood (Study II); lower birth weight, placental size, and head circumference at 12 months predicted a more pronounced positive schitzotypal trait in women (Study III); and thinness and smaller head circumference at birth associated with symptoms of attention-deficit hyperactivity disorder (ADHD) in children who were born at term (Study IV). These associations occured across the whole variation in birth size and after adjusting for several confounders. With respect to growth after birth, individuals with high trait anxiety scores in late adulthood were lighter in weight and thinner in infancy, and gained weight more rapidly between 7 and 11 years of age, but weighed less and were shorter in late adulthood in relation to weight and height measured at 11 years of age (Study II). These results suggest that a suboptimal prenatal environment reflected in smaller birth size may affect a variety of psychological vulnerability factors for mental disorders, such as the temperamental trait of harm avoidance, trait anxiety, schizotypal traits, and symptoms of ADHD. The smaller the birth size across the whole range of variation, the more pronounced were these psychological vulnerability factors. Moreover, some of these outcomes, such as trait anxiety, were also predicted by patterns of growth after birth. The findings are concordant with the DOHaD model, and emphasise the importance of prenatal factors in the aetiology of not only mental disorders but also their psychological vulnerability factors.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The nuclear receptor (NR) superfamily is comprised of receptors for small lipopfilic ligands such as steroid hormones, thyroid hormone, retinoids, and vitamin D. NRs are ligand-inducible transcription factors capable of both activating and repressing their target gene expression. They control a wide range of biological functions connected to growth, development, and homeostasis. In addition to the ligand-regulated receptors, the family includes a large group of receptors whose physiological ligands are unknown. These receptors are referred to as orphan NRs. Estrogen-related receptor gamma (ERRgamma) belongs to the ERR subfamily of orphan NRs together with the related ERRalpha and ERRbeta. ERRs share amino acid sequence homology with the classical estrogen receptors (ERs) but they are unable to bind natural estrogenic ligands. ERRgamma is expressed in several embryonic and adult tissues but its biological role is still largely unknown. ERRgamma activates reporter gene expression in transfected cells independently of added hormones implying that ERRgamma harbors constitutive activity. However, the intrinsic activity of ERRgamma can be inhibited by synthetic compounds such as the selective estrogen receptor modulator 4-hydroxytamoxifen (4-OHT). Ligands of NRs can act as agonists that activate transcription, as antagonists that prevent activation of transcription, or as inverse agonists that antagonize the constitutive transcriptional activity of receptor. Most of the synthetic ERRgamma ligands act as inverse agonists but recently, a synthetic ERRgamma agonist GSK4716 was identified. This demonstrates that it is possible to design and identify agonists for ERRgamma. Prior to this thesis work, the structural and functional characteristics of ERRgamma were largely unknown. The aim of this study was to define the functional requirements for ERRgamma-mediated transcriptional regulation and to examine the cross-talk between ERRgamma and other NRs. Due to the fact that natural physiological ligands of ERRgamma are unknown, another aim of this study was to seek new natural compounds that may affect transcriptional activity of ERRgamma. Plant-derived phytoestrogens have previously been shown to act as ligands for ERs and ERRalpha, and therefore the effects of these compounds were also studied on ERRgamma-mediated transcriptional regulation. This work demonstrated that ERRgamma-mediated transcriptional regulation was dependent on DNA-binding, dimerization and activation function-2. Heterodimerization with ERRalpha inhibited the transcriptional activity of ERRgamma. In addition to 4-OHT, another anti-estrogen, 4-hydroxytoremifene (4-OHtor), was identified as an inverse agonist of ERRgamma. Interestingly, ERRgamma activated transcription in the presence of 4-OHT and 4-OHtor on activator protein-1 binding sites. ERRgamma was found to interact with another orphan NR Nurr1 by repressing the ability of Nurr1 to activate transcription of the osteopontin gene. Transcriptional activity of ERRgamma was shown to be stimulated by the phytoestrogen equol. Structural model analysis and mutational experiments indicated that equol was able to bind to the ligand binding domain of ERRgamma. The growth inhibitory effect of ERRgamma on prostate cancer cells was found to be enhanced by equol. In summary, this study demonstrates that despite the absence of an endogenous physiological ligand, the activity of ERRgamma can be modulated in other ways such as dimerization with related receptors or by cross-talk with other transcription factors as well as by binding some synthetic or natural compounds.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

A national church, freedom of religion, and the state The interpretation of freedom of religion formulated by the Synod of the Evangelical Lutheran Church of Finland in reference to the relationship between the Church and the state from 1963 to 2003 This paper discusses the interpretation of freedom of religion formulated by the Synod of the Evangelical Lutheran Church of Finland during the years 1963-2003. The effect of these formulations and decisions made by the Synod on the relationship between the Church and the state is also discussed as the relationship has been a central issue in the debate about freedom of religion in Finland. Active co-operation with the state caused a dispute in the Church during this period. Another cause for concern for the Synod, a strong defender of the national church, was the weakening position of the Church in a society undergoing many changes. As the Synod of 1963 discussed the status of the Church, the Church began to reflect upon its identity as a national church, and to evaluate freedom of religion in the country, as well as the relationship between the Church and the state. Some of the radicals of the 1960s and 1970s presented the Church as an obstacle to freedom of religion. The Synod was keen to emphasize that, in accordance with international agreements on human rights, freedom of religion means the freedom to have and follow a religion, and also that freedom of religion was a right of the majority in Finnish society. As an active guardian of the rights of its members, the Synod defended such issues as the teaching of religion in schools. Throughout the dispute, the Church focused on its right to act freely and, according to its identity, to express spirituality in the society. At the end of the 1960s, several efforts to reform the law on the freedom of religion and the relationship between the Church and the state gained favour in the Synod. These formulations of the Church were the basis for the work of a parliamentary committee in the 1970s, but no significant changes resulted. Instead, freedom of religion in Finland was judged to be fairly good. The committee paper did, however, lead to preparations for greater independence of the Church. The Synod at the time chose to react to the changes presented to it, but it was not before the 1990s that the Synod became an active force of reform in these matters. Though the Synod, particularly from the 1970s onwards, began clearly to favour the improvement of the position of other religious communities in Finland, it felt it had reason to be cautious as each church and religious community had the freedom to decide individually its relationship with the state. Any changes that would have weakened the position of the Church in Finnish society were met with disapproval in the Synod. Even though some theological concerns regarding the national identity of the Church were raised, the Synod emphasized issues of church policy. Keen to preserve and protect its legal status in society, the Synod judged that this status supported the freedom of action enjoyed by the Church as well as the freedom of religion.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

PROFESSION, PERSON AND WORLDVIEW AT A TURNING POINT A Study of University Libraries and Library Staff in the Information Age 1970 - 2005 The incongruity between commonly held ideas of libraries and librarians and the changes that have occurred in libraries since 2000 provided the impulse for this work. The object is to find out if the changes of the last few decades have penetrated to a deeper level, that is, if they have caused changes in the values and world views of library staff and management. The study focuses on Finnish university libraries and the people who work in them. The theoretical framework is provided by the concepts of world view (values, the concept of time, man and self, the experience of the supernatural and the holy, community and leadership). The viewpoint, framework and methods of the study place it in the area of Comparative Religion by applying the world view framework. The time frame is the information age, which has deeply affected Finnish society and scholarly communication from 1970 to 2005. The source material of the study comprises 30 life stories; somewhat more than half of the stories come from the University of Helsinki, and the rest from the other eight universities. Written sources include library journals, planning documents and historical accounts of libraries. The experiences and research diaries of the research worker are also used as source material. The world view questions are discussed on different levels: 1) recognition of the differences and similarities in the values of the library sphere and the university sphere, 2) examination of the world view elements, community and leadership based on the life stories, and 3) the three phases of the effects of information technology on the university libraries and those who work in them. In comparing the values of the library sphere and the university sphere, the appreciation of creative work and culture as well as the founding principles of science and research are jointly held values. The main difference between the values in the university and library spheres concerns competition and service. Competition is part of the university as an institution of research work. The core value of the library sphere is service, which creates the essential ethos of library work. The ethical principles of the library sphere also include the values of democracy and equality as well as the value of intellectual freedom. There is also a difference between an essential value in the university sphere, the value of autonomy and academic freedom on the one hand, and the global value of the library sphere - organizing operations in a practical and efficient way on the other hand. Implementing this value can also create tension between the research community and the library. Based on the life stories, similarities can be found in the values of the library staff members. The value of service seems to be of primary importance for all who are committed to library work and who find it interesting and rewarding. The service role of the library staff can be extended from information services provider to include the roles of teacher, listener and even therapist, all needed in a competitive research community. The values of democracy and equality also emerge fairly strongly. The information age development has progressed in three phases in the libraries from the 1960s onward. In the third phase beginning in the mid 1990s, the increased usage of electronic resources has set fundamental changes in motion. The changes have affected basic values and the concept of time as well as the hierarchies and valuations within the library community. In addition to and as a replacement for the library possessing a local identity and operational model, a networked, global library is emerging. The changes have brought tension both to the library communities and to the relationship between the university community and the library. Future orientation can be said to be the key concept for change; it affects where the ideals and models for operations are taken from. Future orientation manifests itself as changes in metaphors, changes in the model of a good librarian and as communal valuations. Tension between the libraries and research communities can arise if the research community pictures the library primarily as a traditional library building with a local identity, whereas the 21st century library staff and directors are affected by future orientation and membership in a networked library sphere, working proactively to develop their libraries.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

A national church, freedom of religion, and the state The interpretation of freedom of religion formulated by the Synod of the Evangelical Lutheran Church of Finland in reference to the relationship between the Church and the state from 1963 to 2003 This paper discusses the interpretation of freedom of religion formulated by the Synod of the Evangelical Lutheran Church of Finland during the years 1963-2003. The effect of these formulations and decisions made by the Synod on the relationship between the Church and the state is also discussed as the relationship has been a central issue in the debate about freedom of religion in Finland. Active co-operation with the state caused a dispute in the Church during this period. Another cause for concern for the Synod, a strong defender of the national church, was the weakening position of the Church in a society undergoing many changes. As the Synod of 1963 discussed the status of the Church, the Church began to reflect upon its identity as a national church, and to evaluate freedom of religion in the country, as well as the relationship between the Church and the state. Some of the radicals of the 1960s and 1970s presented the Church as an obstacle to freedom of religion. The Synod was keen to emphasize that, in accordance with international agreements on human rights, freedom of religion means the freedom to have and follow a religion, and also that freedom of religion was a right of the majority in Finnish society. As an active guardian of the rights of its members, the Synod defended such issues as the teaching of religion in schools. Throughout the dispute, the Church focused on its right to act freely and, according to its identity, to express spirituality in the society. At the end of the 1960s, several efforts to reform the law on the freedom of religion and the relationship between the Church and the state gained favour in the Synod. These formulations of the Church were the basis for the work of a parliamentary committee in the 1970s, but no significant changes resulted. Instead, freedom of religion in Finland was judged to be fairly good. The committee paper did, however, lead to preparations for greater independence of the Church. The Synod at the time chose to react to the changes presented to it, but it was not before the 1990s that the Synod became an active force of reform in these matters. Though the Synod, particularly from the 1970s onwards, began clearly to favour the improvement of the position of other religious communities in Finland, it felt it had reason to be cautious as each church and religious community had the freedom to decide individually its relationship with the state. Any changes that would have weakened the position of the Church in Finnish society were met with disapproval in the Synod. Even though some theological concerns regarding the national identity of the Church were raised, the Synod emphasized issues of church policy. Keen to preserve and protect its legal status in society, the Synod judged that this status supported the freedom of action enjoyed by the Church as well as the freedom of religion.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Glial cell line-derived neurotrophic factor (GDNF) family ligands: GDNF, neurturin, persephin and artemin, signal through a receptor tyrosine kinase Ret by binding first to a co-receptor (GFRα1-4) that is attached to the plasma membrane. The GDNF family factors can support the survival of various peripheral and central neuronal populations and have important functions also outside the nervous system, especially in kidney development. Activating mutations in the RET gene cause tumours in neuroendocrine cells, whereas inactivating mutations in RET are found in patients with Hirschsprung s disease (HSCR) characterized by loss of ganglionic cells along the intestine. The aim of this study was to examine the in vivo functions of neurturin receptor GFRα2 and persephin receptor GFRα4 using knockout (KO) mice. Mice lacking GFRα2 grow poorly after weaning and have deficits in parasympathetic and enteric innervation. This study shows that impaired secretion of the salivary glands and exocrine pancreas contribute to growth retardation in GFRα2-KO mice. These mice have a reduced number of intrapancreatic neurons and decreased cholinergic innervation of the exocrine pancreas as well as reduced excitatory fibres in the myenteric plexus of the small intestine. This study also demonstrates that GFRα2-mediated Ret signalling is required for target innervation and maintenance of soma size of sympathetic cholinergic neurons and sensory nociceptive IB4-binding neurons. Furthermore, lack of GFRα2 in mice results in deficient perception of temperatures above and below thermoneutrality and in attenuated inflammatory pain response. GFRα4 is co-expressed with Ret predominantly in calcitonin-producing thyroid C-cells in the mouse. In this study GFRα4-deficient mice were generated. The mice show no gross developmental deficits and have a normal number of C-cells. However, young but not adult mice lacking GFRα4 have a lower production of calcitonin in thyroid tissue and consequently, an increased bone formation rate. Thus, GFRα4/Ret signalling may regulate calcitonin production. In conclusion, this study reveals that GFRα2/Ret signalling is crucial for the development and function of specific components of the peripheral nervous system and that GFRα4-mediated Ret signalling is required for controlling transmitter synthesis in thyroid C-cells.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The availability of oxygen has a major effect on all organisms. The yeast Saccharomyces cerevisiae is able to adapt its metabolism for growth in different conditions of oxygen provision, and to grow even under complete lack of oxygen. Although the physiology of S. cerevisiae has mainly been studied under fully aerobic and anaerobic conditions, less is known of metabolism under oxygen-limited conditions and of the adaptation to changing conditions of oxygen provision. This study compared the physiology of S. cerevisiae in conditions of five levels of oxygen provision (0, 0.5, 1.0, 2.8 and 20.9% O2 in feed gas) by using measurements on metabolite, transcriptome and proteome levels. On the transcriptional level, the main differences were observed between the three level groups, 0, 0.5 2.8 and 20.9% O2 which led to fully fermentative, respiro-fermentative and fully respiratory modes of metabolism, respectively. However, proteome analysis suggested post-transcriptional regulation at the level of 0.5 O2. The analysis of metabolite and transcript levels of central carbon metabolism also suggested post-transcriptional regulation especially in glycolysis. Further, a global upregulation of genes related to respiratory pathways was observed in the oxygen-limited conditions and the same trend was seen in the proteome analysis and in the activities of enzymes of the TCA cycle. The responses of intracellular metabolites related to central carbon metabolism and transcriptional responses to change in oxygen availability were studied. As a response to sudden oxygen depletion, concentrations of the metabolites of central carbon metabolism responded faster than the corresponding levels of gene expression. In general, the genome-wide transcriptional responses to oxygen depletion were highly similar when two different initial conditions of oxygen provision (20.9 and 1.0% O2) were compared. The genes related to growth and cell proliferation were transiently downregulated whereas the genes related to protein degradation and phosphate uptake were transiently upregulated. In the cultures initially receiving 1.0% O2, a transient upregulation of genes related to fatty acid oxidation, peroxisomal biogenesis, response to oxidative stress and pentose phosphate pathway was observed. Additionally, this work analysed the effect of oxygen on transcription of genes belonging to the hexose transporter gene family. Although the specific glucose uptake rate was highest in fully anaerobic conditions, none of the hxt genes showed highest expression in anaerobic conditions. However, the expression of genes encoding the moderately low affinity transporters decreased with the decreasing oxygen level. Thus it was concluded that there is a relative increase in high affinity transport in anaerobic conditions supporting the high uptake rate.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The Baltic Sea is a geologically young, large brackish water basin, and few of the species living there have fully adapted to its special conditions. Many of the species live on the edge of their distribution range in terms of one or more environmental variables such as salinity or temperature. Environmental fluctuations are know to cause fluctuations in populations abundance, and this effect is especially strong near the edges of the distribution range, where even small changes in an environmental variable can be critical to the success of a species. This thesis examines which environmental factors are the most important in relation to the success of various commercially exploited fish species in the northern Baltic Sea. It also examines the uncertainties related to fish stocks current and potential status as well as to their relationship with their environment. The aim is to quantify the uncertainties related to fisheries and environmental management, to find potential management strategies that can be used to reduce uncertainty in management results and to develop methodology related to uncertainty estimation in natural resources management. Bayesian statistical methods are utilized due to their ability to treat uncertainty explicitly in all parts of the statistical model. The results show that uncertainty about important parameters of even the most intensively studied fish species such as salmon (Salmo salar L.) and Baltic herring (Clupea harengus membras L.) is large. On the other hand, management approaches that reduce uncertainty can be found. These include utilising information about ecological similarity of fish stocks and species, and using management variables that are directly related to stock parameters that can be measured easily and without extrapolations or assumptions.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This study analyses personal relationships linking research to sociological theory on the questions of the social bond and on the self as social. From the viewpoint of disruptive life events and experiences, such as loss, divorce and illness, it aims at understanding how selves are bound to their significant others as those specific people ‘close or otherwise important’ to them. Who form the configurations of significant others? How do different bonds respond in disruptions and how do relational processes unfold? How is the embeddedness of selves manifested in the processes of bonding, on the one hand, and in the relational formation of the self, on the other? The bonds are analyzed from an anti-categorical viewpoint based on personal citations of significance as opposed to given relationship categories, such as ‘family’ or ‘friendship’ – the two kinds of relationships that in fact are most frequently significant. The study draws from analysis of the personal narratives of 37 Finnish women and men (in all 80 interviews) and their entire configurations of those specific people who they cite as ‘close or otherwise important’. The analysis stresses the subjective experiences, while also investigating the actualized relational processes and configurations of all personal relationships with certain relationship histories embedded in micro-level structures. The research is based on four empirical sub-studies of personal relationships and a summary discussing the questions of the self and social bond. Discussion draws from G. H. Mead, C. Cooley, N. Elias, T. Scheff, G. Simmel and the contributors of ‘relational sociology’. Sub-studies analyse bonds to others from the viewpoint of biographical disruption and re-configuration of significant others, estranged family bonds, peer support and the formation of the most intimate relationships into exclusive and inclusive configurations. All analyses examine the dialectics of the social and the personal, asking how different structuring mechanisms and personal experiences and negotiations together contribute to the unfolding of the bonds. The summary elaborates personal relationships as social bonds embedded in wider webs of interdependent people and social settings that are laden with cultural expectations. Regarding the question of the relational self, the study proposes both bonding and individuality as significant. They are seen as interdependent phases of the relationality of the self. Bonding anchors the self to its significant relationships, in which individuality is manifested, for example, in contrasting and differentiating dynamics, but also in active attempts to connect with others. Individuality is not a fixed quality of the self, but a fluid and interdependent phase of the relational self. More specifically, it appears in three formats in the flux of relational processes: as a sense of unique self (via cultivation of subjective experiences), as agency and as (a search for) relative autonomy. The study includes an epilogue addressing the ambivalence between the social expectation of individuality in society and the bonded reality of selves.